The art of reducing surface reflection of a display device having been attracting attention is a moth-eye structure which can provide an ultra-antireflection effect without conventional light interference films. A moth-eye structure, as described in Patent Literature 1, for example, is formed by arranging projection and recess patterns continuously on the surface of the target product of anti-reflection treatment. These patterns include projections arranged at intervals equal to or smaller than the visible light wavelength, which are smaller than the intervals in the projection and recess patterns formed on anti-glare (AG) films. The moth-eye structure with such patterns provide pseudo-continuous changes in the refractive index in the interface between the outside (air) and the product surface, so as to transmit almost all light regardless of the refractive index interface, almost perfectly eliminating light reflection on the product surface.
A film having such a moth-eye structure (hereinafter, also referred to as a moth-eye film) is applicable to various uses such as displays for devices (e.g. TVs, cellphones), measuring instruments (e.g. speedometers and fuel gauges for cars), and construction materials (e.g. windowpanes, road signs).
Such a moth-eye film needs to be adhered to the outermost surface of the product because it transmits light by pseudo elimination of changes in the refractive index in the air interface. For example, in the case that a moth-eye film is adhered to the surface of a windowpane, condensation occurs on the surface of the moth-eye film adhered to the windowpane as illustrated in FIG. 51 in the winter morning in which the outside air is cold, and the generated droplets of water flow down to cause stains at the bottom of the windowpane.
In addition to moth-eye films, various studies have been made on the method of preventing condensation on the surface of materials such as construction materials. These studies typically focus on the contact angle between the product surface and water (e.g. Patent Literature documents 2 to 6).